This study explores the potential of the naphthalene sublimation technique to be used to analyze the manner in which surfaces regress, specifically focusing on the effect that skin friction has on regression and vice versa. For this experimentation, a flat steel plate installed with three skin friction sensors was coated with naphthalene via a mechanized sprayer and was installed in the wall of the Ahmic Aerospace Turbulent Boundary Layer Research supersonic wind tunnel. The plate and sensor configuration was subjected to three subsequent tunnel runs at Mach 2.31. This process was repeated at plenum pressures of 0.35 MPa and 0.69 MPa, which correspond to Reynolds Numbers of 1.4x10^7/m and 2.8x10^7/m. Between the first and final run, a -4.7% and -3.7% percent change in the coefficient of friction was seen at the 0.35 MPa and 0.69 MPa plenum conditions, respectively. Images of the plate taken before and after each run qualitatively indicate continual naphthalene regression with each subsequent tunnel run. This decrease in the coefficient of friction was attributed in part to the regression of the naphthalene coating, indicating that this method has the potential to be used to study the interaction between skin friction and regressing surfaces. Additionally, this study showed that it is certainly possible to measure skin friction with sensors where both the head of the movable sensor element and the surrounding wall is coated with sprayed naphthalene. / Master of Science / This study explores the potential of using an experimental method to better understand how surfaces recede when subjected to moving air. A chemical called naphthalene was used because naphthalene naturally recedes very easily, unlike many other materials which a researcher would want to study the receding behavior of, making it an ideal choice for this study. Sensors made to detect the amount of force generated by flowing air over a surface were installed into a flat metal plate. The plate was coated with naphthalene and installed into the wall of a wind tunnel, which generates airflow over the plate to simulate flight conditions. Three separate and sequential airflow runs over the plate were conducted.
This process was repeated under two different air conditions. In both conditions, a decrease in the amount of force due to the air moving over the plate was detected as subsequent runs were conducted and the naphthalene receded. This indicates the method has the potential to be used to study how other surfaces recede when subjected to moving air.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/113914 |
| Date | 22 February 2023 |
| Creators | Hall, Grace Alexandra |
| Contributors | Aerospace and Ocean Engineering, Schetz, Joseph A., Artis, Harry Pat, Young, Gregory |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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